The Metropolitan Police has begun a criminal inquiry into Harry Cohen after he claimed more than £70,000 for a “second home” while renting out his main property.

Today, three other MPs, Elliot Morley, David Chaytor and Jim Devine, will appear in court for the first time after being charged last month with multiple offences under the Theft Act.

Detectives are also investigating Eric Illsley, the MP for Barnsley, after he allegedly made “phantom” claims for council tax.

Over the past few weeks, the Met police are understood to have approached the House of Commons authorities seeking documents relating to claims made by Mr Cohen, making him the fifth Labour MP to be the subject of a criminal investigation since The Daily Telegraph exposed the expenses scandal last year.

The Labour MP has already been heavily censured by the parliamentary authorities.

Between 2004 and 2009, Mr Cohen told the parliamentary authorities that his main home was in Colchester and his second home in his constituency in Wanstead, east London.

According to House of Commons rules, MPs must spend the majority of their time in their main home if they want to claim expenses for another property.

However, during part of this period – including the entire 2005-06 financial year – Mr Cohen, 60, rented out the Colchester property to tenants. In total, he made a gross income of £27,000 by renting out the house, while living in his second home.

The MP defended the claims by saying that his wife had fallen ill and was unable to travel.

He said that, in order to care for her and attend to constituency business, he had to live most of the time in east London. He said that he always intended to return to his “main home”, adding: “I consider it a home of beauty… I feel that angels reside there.”

In the meantime, he spent thousands of pounds renovating the constituency property, including spending £1,741 on granite kitchen worktops, £3,131 on plastering and £1,470 on decorations. He is now attempting to sell his designated second home for £475,000 — £100,000 more than he paid for it.

John Lyon, the Parliamentary Commissioner for Standards, said that Mr Cohen’s claims represented a “particularly serious breach of the rules”. The MP apologised and said he “would not intentionally have wanted to do anything to tarnish Parliament’s reputation”.

The MP has announced that he will retire at the next election but his “golden” parachute payment of £64,766 will be withheld as punishment for his dubious expense claims.

The decision by the police to investigate an MP already censured by the parliamentary authorities is likely to prove controversial.

Other MPs have argued that it is for Parliament, not the courts, to punish politicians found to have abused their expense claims.

However, a well-placed Whitehall source said: “There is nothing to stop the Metropolitan Police becoming involved in potentially serious cases of abuse. The fact that Cohen has already been punished by some sort of parliamentary quasi court is not an issue which is causing Scotland Yard any problem.”

The Daily Telegraph has learnt that Mr Morley, Mr Chaytor and Mr Devine will today set out their case to have the charges against them thrown out. In the unprecedented appearance before Westminster magistrates, their solicitor will read a statement arguing that they are protected from prosecution by parliamentary privilege. Lord Hanningfield, a Conservative peer, will also appear in court after being charged over his House of Lords claims.